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We use idealised N-body simulations of equilibrium discs in live and static haloes to study how dark matter co-evolution impacts the assembly of stellar particles into a bar and the halo response. Initial conditions correspond to a…

Astrophysics of Galaxies · Physics 2024-08-08 Matthew Frosst , Danail Obreschkow , Aaron D. Ludlow

Galactic bars drive the internal evolution of spiral galaxies, while their formation is tightly coupled to the properties of their host galaxy and dark matter halo. To explore what drives bar formation in the cosmological context and how…

Astrophysics of Galaxies · Physics 2025-03-05 Francesca Fragkoudi , Robert Grand , Rüdiger Pakmor , Facundo Gómez , Federico Marinacci , Volker Springel

More than 50 per cent of present-day massive disc galaxies show a rotating stellar bar. Their formation and dynamics have been widely studied both numerically and observationally. Although numerical simulations in the $\Lambda$CDM…

Astrophysics of Galaxies · Physics 2022-01-17 Ornela F. Marioni , Mario G. Abadi , Stefan Gottlöber , Gustavo Yepes

The dynamic evolution of galactic bars in standard $\Lambda$CDM models is dominated by angular momentum loss to the dark matter haloes via dynamical friction. Traditional approximations to dynamical friction are formulated using the…

Astrophysics of Galaxies · Physics 2022-04-29 Rimpei Chiba , Ralph Schönrich

We study evolution of galactic bars using suite of very high-resolution zoom-in cosmological simulations of galaxies at z ~ 9-2. Our models were chosen to lie within similar mass DM halos, log(Mvir/Mo) ~ 11.65 +- 0.05, at z=6, 4, and 2, in…

Astrophysics of Galaxies · Physics 2022-08-03 Da Bi , Isaac Shlosman , Emilio Romano-Diaz

Galactic bars are found in the majority of disc galaxies. They rotate nearly rigidly with an angular frequency called pattern speed. Previous idealised simulations have shown that bar pattern speed decreases with time due to dynamical…

Astrophysics of Galaxies · Physics 2024-12-11 Marcin Semczuk , Walter Dehnen , Ralph Schönrich , E. Athanassoula

We use $N$-body simulations to investigate the distinct bar formation processes in disks residing in halos of various concentrations. In a highly concentrated halo, the bar development is limited by the dominant multi-arm modes as a result…

Astrophysics of Galaxies · Physics 2026-01-27 T. Worrakitpoonpon

We interpret simulations of secularly-evolving disc galaxies through orbit morphology. Using a new algorithm that measures the volume of orbits in real space using a tessellation, we rapidly isolate commensurate (resonant) orbits. We…

Astrophysics of Galaxies · Physics 2021-04-30 Michael S. Petersen , Martin D. Weinberg , Neal Katz

The spin of dark halos has been shown to significantly affect bar formation and evolution in disk galaxies. To understand the physical role of the halo spin on bar formation, we run $N$-body simulations of isolated, Milky Way-sized galaxies…

Astrophysics of Galaxies · Physics 2024-06-14 Dajeong Jang , Woong-Tae Kim

Bars in disk galaxies slow down as they transfer their angular momentum to their dark matter halo via dynamical friction from near-resonant orbits. This bar-halo dynamical friction can become ineffective once phase mixing erases the…

Astrophysics of Galaxies · Physics 2026-03-16 Rumi Kodama , Rimpei Chiba , Tetsuro Asano , Junichi Baba , Michiko Fujii

We study the properties of two bars formed in fully cosmological hydrodynamical simulations of the formation of Milky Way-mass galaxies. In one case, the bar formed in a system with disc, bulge and halo components and is relatively strong…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Cecilia Scannapieco , Evangelia Athanassoula

We study the dynamical interactions of mass systems in equilibrium under their own gravity that mutually exert and experience gravitational forces. The method we employ is to model the dynamical evolution of two isolated bars, hosted within…

Astrophysics of Galaxies · Physics 2017-07-12 F. Garzon , M. Lopez-Corredoira

Using high resolution N-body simulations of stellar disks embedded in cosmologically motivated dark matter halos, we study the evolution of bars and the transfer of angular momentum between halos and bars. We find that dynamical friction…

Astrophysics · Physics 2009-11-07 Octavio Valenzuela , Anatoly Klypin

I review the arguments for the importance of halo structure in driving galaxy evolution and coupling a galaxy to its environment. We begin with a general discussion of the key dynamics and examples of structure dominated by modes. We find…

Astrophysics · Physics 2007-05-23 Martin D. Weinberg

The halo plays a crucial role in the evolution of barred galaxies. Its near-resonant material absorbs angular momentum emitted from some of the disc particles and helps the bar become stronger. As a result, a bar (oval) forms in the inner…

Astrophysics · Physics 2015-06-24 E. Athanassoula

We have done a detailed study on the structural and kinematical properties of lenticular and early- and late-type spiral galaxies with bars, aiming to explore the formation and evolution processes of stellar bars in galaxies, and their…

Astrophysics · Physics 2009-11-10 Dimitri Alexei Gadotti

Disk galaxies can exchange angular momentum and baryons with their host dark matter (DM) halos. These halos possess internal spin, `lambda', which is insignificant rotationally but does affect interactions between the baryonic and DM…

Astrophysics of Galaxies · Physics 2019-09-11 Angela Collier , Isaac Shlosman , Clayton Heller

We analyze the evolution of stellar bars in galactic disks in mildly triaxial flat-core and cuspy CDM halos. We use tailored simulations of rigid and live halos which include the feedback from disk/bar onto the halo in order to test the…

Astrophysics · Physics 2009-11-10 Ingo Berentzen , Isaac Shlosman , Shardha Jogee

Stellar bars in disk galaxies grow as stars in near circular orbits lose angular momentum to their environments, including their Dark Matter (DM) halo, and transform into elongated bar orbits. This angular momentum exchange during galaxy…

Astrophysics of Galaxies · Physics 2024-10-04 Sioree Ansar , Mousumi Das

There is now clear evidence, from a variety of studies, that galactic bars contribute to and/or accelerate processes which quench galaxies. However, bars have a variety of strengths and pattern speeds, and previous work has suggested that…

Astrophysics of Galaxies · Physics 2026-04-22 Petra Mengistu , Karen L. Masters , Tobias Geron , R. J. Smethurst , Chris Lintott , B. D. Simmons